Print to cut register system

ABSTRACT

A print to cut register system for establishing and maintaining registration between a pattern on a moving web and a cutting die by controlling the operative condition of a pair of web feed rolls. The print to cut register system incorporates an electric signal means responsive to the output of a registration error detector. The electric signal means, which may include a computing resolver, provides an output signal proportional to the alteration in the web feed rolls necessary to correct the detected registration error. The electric signal means is connected to electromechanical means having a servomotor for converting the output signal of the electric signal means into a corresponding shaft speed and rotary direction signal. The servomotor shaft speed and rotary direction signal is amplified by the torque amplifier and provided through a differential drive means to the feed rolls to correct the registration error.

United States Patent [72] Inventor CharlesR.Edson West Allies, Wis. [2]] App]. No. 878,692 [22] Filed Nov. 21, 1969 [45] Patented Sept. 28, 1971 [73] Assignee Zerand Corporation New Berlin, Wis.

[54] PRINT TO CUT REGISTER SYSTEM 17 Claims, 8 Drawing Figs.

[52] US. Cl 226/31 [51] Int. Cl B65h 23/18 [50] Field of Search 226/2, 30, 31, 27-29 [56] References Cited UNITED STATES PATENTS 2,230,715 2/1941 Cockrell 226/31 2,250,209 7/1941 Shoults..... 226/31 2,583,580 1/1952 Ludwig 226/31 Primary ExaminerRichard A. Schacher Attorney-James E. Nilles ABSTRACT: A print to cut register system for establishing and maintaining registration between a pattern on a moving web and a cutting die by controlling the operative condition of a pair of web feed rolls. The print to cut register system incorporates an electric signal means responsive to the output of a registration error detector. The electric signal means, which may include a computing resolver, provides an output signal proportional to the alteration in the web feed rolls necessary to correct the detected registration error, The electric signal means is connected to electromechanical means having a servomotor for converting the output signal of the electric signal means into a corresponding shaft speed and rotary direction signal. The servomotor shaft speed and rotary direction signal is amplified by the torque amplifier and provided through a differential drive means to the feed rolls to correct the registration error.

PRINT TO CUT REGISTER SYSTEM BACKGROUND OF THE lNVENTlON 1. Field of the Invention The present invention relates to print to cut register systems suitable for use with web-treating apparatus.

2. Description of the Prior Art The present invention relates to control apparatus for equipment which treats a moving web or strip of material. The invention is more specifically directed to a print to cut register system for maintaining synchronization between a pattern printed on the web and a cutter press or punch which forms blanks for cartons and the like from the printed web. The synchronization of the web pattern with the operation of the cutter press is often termed registration or register," the terms being used interchangeably herein.

Web treating apparatus of the type with which the present invention is employed may typically include one or more printing sections in which the desired pattern is placed on the web by rotating cylindrical printing plates as the web moves continuously through the printing sections. When a previously printed web is undergoing treatment, the web-treating apparatus may include an unwind stand which continuously pays out the web at a constant rate.

The operation of the cutter press requires that the web be stationary as a reciprocating die portion of the press ascends onto the web to cut the web and form the blank. For this cutting operation the web is intermittently fed into the press, held stationary during the cutting, and then removed from the press. As can be readily appreciated, the registration or synchronization which must be maintained between the printed pattern and the cutting dies, so as to insure, for example, that labels appear in the proper place on the finished carton blank, is made more difficult by the intermittent stopping and starting of the web during the cyclical operation of the cutter press.

To coordinate the operation of the printing section or unwind stand, through which the web moves continuously, with the cutter press, through which the web moves intermittently, a pair of continuously active metering feed rolls are utilized to supply the web to the cutter press at a precise rate. The web so fed then passes through a pair of intermittently, active feed rolls which actually place the web fed by the continuously active metering feed rolls in the cutter press. A brake bar is pro vided between the continuously active metering feed rolls and the intermittently active feed rolls to arrest the travel of the moving web during the cutting stroke of the press. A slack loop is built up in the web between the brake bar and the continuously active metering feed rolls during each stroke of the press. This slack loop is then taken up by the intermittently active feed rolls during the next operation of the cutter press. The length of web fed by the continuously active metering feed rolls into the slack loop during each stroke or cyclical operation of the press is termed the repeat length. The repeat length of the web determines the amount of material fed into the cutter press during each operation. The rotary speed of the metering feed rolls, in turn, determines the amount of web material fed into the slack loop and the repeat length.

It will be appreciated that as one cycle of operation of the cutter press may be used to form a blank of any size, the intermittent or cyclical operation of the cutter press is independent of the size of the blank being formed so that the operation of the press may proceed at a uniform repetitive rate. The rotational speed of the continuously active metering feed rolls, on the other hand, is directly responsive to the repeat length of the web and the size of the blank being formed. Hence, the rotational speed of the continuously active metering feed rolls must vary with the size of the pattern placed on the web in order to provide the desired repeat length: for short patterns and repeat lengths the metering feed rolls turn less for each operation of the press and for long patterns and repeat lengths the metering feed rolls must turn more. To accommodate all sizes of patterns and repeat lengths, the continuously active LII metering feed rolls must be driven at a variable speed dependent on the desired repeat length. This requires the speed of the continuously active metering feed rolls to be infinitely variable.

The speed of the continuously active metering feed rolls must also be varied to correct registration errors appearing between the web pattern and the cutter press die. These registration errors may be characterized] as being of two general types. The first type is a constant error and occurs when the correct repeat length is being fed to the cutter press but the position of the pattern with respect to the cutting die of the press is faulty. For example, a pattern of the desired repeat length may continually be fed to the cutting press 0.01 inches short of its desired position. This type of registration error may hereinafter be termed a position registration error and is correctable by a momentary increase in the speed of the continu ously active metering feed rolls which advances the web pattern to the desired position. The second type of registration error is a cumulative type and occurs when the repeat length is incorrect. Thus, the repeat length of web provided to the cutter press may be 0.01 inches shorter than necessary to provide proper registration. This registration error of 0.01 inch will appear on the finished blank. On the next operation of the cutter press, an additional repeat length, also 0.01 inch shorter than necessary is fed to the cutting press. The registration error appearing in the finished blank will now be 0.02 inches because of the two successive operations during which the repeat length of the web was 0.01 inches too short. On the third operation, the registration error will total 0.03 inch. It will therefore be apparent that even small errors in the web repeat length, termed repeat length errors, will have a deleterious effect on web registration because of their cumulative effect. Repeat length errors are correctable by altering the rotary speed of the metering feed rolls on a continuous basis so as to provide the correct repeat length of web to the cutter press.

The continuously active metering feed rolls of the web treating apparatus are generally driven through mechanical linkage from the crankshaft providing reciprocation to the cutting die of the press so that the rolls are activated any time the cutter press is operated. However, as the crankshaft and cutter press operate at a constant speed, it will be readily appreciated that driving the metering rolls from this source can provide only unifomi speed to the rolls rather than the desired infinitely variable and controllable speed.

While a change gearbox may be inserted along the shafting between the cutter press and the metering rolls, gearing alone cannot provide infinitely variable and controllable speed to the feed rolls because of the discrete ratios found in gear drives. Neither can changing the diameter of the rolls.

While infinitely variable drives, as for example, a variablediameter pulley drive may be used, they are subject to drift, a random change in speed with time, which alters the repeat length provided by the metering rolls and destroys the desired registration.

The prior art has been able to overcome the shortcoming of both gear drives and variable-speed drives and provide a satisfactory print to cut register system only through the use of a drive system which is complex, cumbersome, and expensive. This system utilizes two differentials, a change gearbox, an infinitely variable ratio drive including the associate ratio regulating apparatus, an adjusting motor, a hydraulic compensator motor and its solenoid valve and hydraulic pump, and an electromechanical brake. In such a system, the cutter press crankshaft is connected through the change gearbox to one input of one of the differentials. This differential is generally termed the primary differential. The output shaft of the primary differential is connected to the continuously active metering feed rolls. The input of the infinitely variable ratio drive is connected to a power takeoff on the output shaft of the primary differential. The output shaft of the variable ratio drive is connected to one of the inputs of a second differential termed the secondary differential. By varying the coupling ratio between the input and output shafts, the drive provides an infinitely variable ratio range to its output shaft over some definite ratio range. The infinitely variable ratio drive may typically be of the variable diameter pulley type having a motor for altering the diameters of the pulleys and the shaft coupling ratio.

The output shaft of the secondary differential is connected to the second input of the primary differential. The other input of the secondary differential is connected to a hydraulic motor.

In operation, the gear ratio of the change gearbox is selected so that the output shaft of the gearbox drives the metering feed rolls through the primary differential at a speed which provides, as closely as possible, the desired repeat length to the web, within the limits of the available gear ratios in the gearbox. The variable ratio drive is adjusted to furnish, through the primary and secondary differentials, the alteration in the metering feed roll speed necessary to yield precisely the desired repeat length of web. The aforesaid alteration in metering feed roll speed is obtained by adjusting the ratio of the output shaft of the variable ratio drive to a level such that when the drive output shaft speed is added to, the speed of the output shaft of the primary differential, a corrective speed increment is applied to the metering roll speed established by the change gearbox. In this manner, drift in the variable speed drive causes a negligible speed variation in the overall speed of the feed rolls because it acts only on the generally small corrective speed increment provided by the variable ratio drive.

Under such conditions, if a position registration error appears between the web pattern and the cutting die, the hydraulic motor is operated to momentarily alter the speed of the feed rolls through the primary and secondary differentials to correct this error. The hydraulic motor thus serves as a position error correcting means. To correct a position registration error, the coupling ratio of the variable ratio drive is not altered.

However, if a repeat length error appears in the web-treating apparatus, the coupling ratio in the variable ratio drive is readjusted to change the metering feed roll speed in a manner such as to provide the desired repeat length to the web.

From the foregoing, it is apparent that heretofore available print to cut register systems, while they have provided reasonably satisfactory register control, have been exceedingly complex. This complexity has made them costly to construct and, because of a propensity to malfunction and break down, costly to both operate and maintain.

As major components of such prior art systems were driven by the main mechanical linkage between the cutter press and the continuously active metering feed rolls, most of the system elements, of necessity, had to be of a size capable of handling all the mechanical power transmitted through the main linkage. The control portions of the system had to be similarly sized so that the register systems tended to be cumbersome as well as complex.

Further, such print to cut register systems have been unable to correct or compensate for known registration errors without actually operating the cutter press. These known errors, like those occurring during the normal operation of the cutter press, C(Luld only be removed by actual operation of the press. This has resulted in wastage of the web material.

SUMMARY OF THE PRESENT INVENTION It is, therefore, the object of the present invention to provide an improved print to cut register system suitable for use with web-treating apparatus.

It is a further object of the present invention to provide such a print to cut register system which is simple and economical in construction and operation and which is capable of substantially trouble-free operation for substantial periods of time.

Another object of the present invention is to provide a print to cut register system which permits known registration errors existing in the web-treating apparatus to be corrected or compensated for prior to operation of the web treating apparatus.

The simplicity and economy of the print to cut register system of the present invention, in great measure, may be attributed to the incorporation of electric signal converting means and signal summing means in the system. These signal means provide an electric signal corresponding to the metering feed roll speed alteration necessary to effect proper registration. Power-amplifying elements are employed to change the electric signal into a register correcting speed alteration of the metering feed rolls. In this manner, the mechanical complexity of prior art print to cut register systems, driven by the cutter press-feed roll linkage, is avoided. At the same time, the use of small, compact electronic and electromechanical components in regulating the corrective action of the print to cut register system is permitted.

Briefly, the present invention provides a print to cut register system for providing registration between successive portions of a moving web and a web-treating apparatus cyclically applied to each of the web portions, as for example, to cut a blank from the web. The web-treating apparatus includes controllable metering rolls located upstream along the web for regulating the length of the web portion provided to the webtreating apparatus during each cycle of operation and the registration of the portions with said apparatus in accordance with the rotary condition of the metering rolls. The web-treating apparatus further includes a registration error detector for detecting the registration error between the web-treating apparatus and successive portions of the web and providing an error signal accordingly. A differential drive means rotates the metering rolls to establish their rotary condition.

The print to cut register system includes a signal-converting means having an input responsive to the error signal of the registration error detector for converting the error signal into an output signal corresponding to a registration correcting alteration in the rotary condition of the metering rolls. An electromechanical means having a rotatable output member drivingly coupled to the differential drive means is included in register system for altering the rotary condition of the metering rolls in accordance with the rotary condition of the output member. The electromechanical means has an input responsive to the output signal of the signal converting means for altering the rotary condition of the output member in accordance with the output signal to provide registration between the web portions and the web-treating apparatus.

The print to cut register system may also include a summing means which sums the output signal of the converting means with an additional error signal produced by the registration error detector responsive to the registration error existing during each cycle of operation of the web-treating apparatus so that the alteration of the metering feed roll rotary condition is responsive to both signals.

The print to cut register system provides for the correction of known registration errors by including means for altering the output signal of the converting means or summing means independently of the error signals of the registration error detector.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a somewhat diagrammatic view of a web-treating apparatus including the print to cut register system of the present invention, the latter being shown in generalized block diagram form;

FIG. 2 is a detailed schematic diagram of the print to cut register system of the present invention;

FIG. 3 is a schematic diagram, similar to FIG. 2, showing the operation of the print to cut register system of the present invention in correcting position registration errors;

FIG. 4 is a schematic diagram, similar to FIG. 2, showing the operation of the print to cut register system of the present invention in correcting repeat length errors; and

FIGS. 5a, b, c and d are partial schematic diagrams showing other embodiments of the print to cut register system of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT The Web-Treating Apparatus As shown in FIG. 1, web-treating apparatus 10 includes an unwind stand 12 on which is placed the web 14 in roll form. It may be assumed that a pattern 16 has been printed on web 14 by a previous processing step. Registration marks 18, bearing a fixed locational relationship to the pattern 16, may also be applied along one edge of the web.

The web 14 passes from unwind stand 12 to cutter press 22 in the direction indicated by the arrow in FIG. 1. The web initially passes through continuously active metering feed rolls 26 and 28. These continuously active rolls establish the repeat length of the web by feeding it at a precise rate to the cutter press. Continuously active feed rolls 26 and 28 are driven by a drive means, hereinafter described in detail.

The web next passes through a pair of brake bars 30 and 32, the lower bar 30 of which may be vertically reciprocal for intermittent clamping engagement with the fixed upper bar 32, to thereby stop the web when the operation of cutter press 22 occurs and to form a slack loop 14a in the web. The brake bars then release the web to permit intermittently active feed rolls 34 and 36 to provide another repeat length of web 14 to the cutter press.

Cutter press 22 includes an upper, fixed platen 40 and a vertically reciprocal cutting die 46 which is movable toward and away from fixed platen 40. Cutting die 46 is reciprocated by connecting rod 48 which is journaled at its upper end on shaft 50 carried by cutting die 46. The lower end of connecting rod 48 is mounted on crankshaft 52 driven by an electric motor 54.

Cam shaft 82 which is diagrammatically shown as an extension of crankshaft 52 operates brake bars 30 and 32 and intermittently active feed rolls 34 and 36 for shifting the brake bars into clamping engagement with web 14 and for inactivating intermittently active feed rolls 34 and 36 during the operation of cutter press 22.

The cut out blanks 16a formed from pattern 16 on web 14 are moved down chute 44 to storage area 42.

The Register Error Detector The web-treating apparatus includes a register error detector which detects both positional registration errors and repeat length registration errors and provides an output signal responsive to such errors which may be utilized for operation of the print to cut register system of the present invention. The position of the web pattern 16 with respect to the cutter press is ascertained through the use of register marks 18 on web 14. Photoelectric cell 70 is positioned a predetermined distance from cutter press 22 and in a manner such that a passage of a register mark 18 causes photoelectric cell 70 to generate an output signal in the form of an electric pulse.

The operative condition of cutter press 22 is sensed by a switch which is operatively driven by crankshaft 52 and hence coordinated with the operation of cutter press 22. As typically shown in FIG. 1, a cam 72 is mounted on crankshaft 52 for moving the movable element 74 of switch 76 as crankshaft 52 rotates to open and close the switch and provide an output signal therefrom.

In essence, the registration error is detected by a coincidence detector. The photoelectric cell 70 and switch 76 are operated such that if the operation of cutter press 22 is in exact synchronization with the pattern 16 on web 14, so that cutting die 46 engages and cuts web 14 in registration with the pattern, photoelectric cell 70 and switch 76 will generate signals simultaneously, or in coincidence. A circuit is provided to detect this coincidental signal generation, or the lack thereof, if pattern 16 is out of registration with cutting die 46, and to provide an output signal accordingly. Additional circuitry is provided in the register error detector to detect the magnitude of asynchronous signal generation so as to provide an output signal indicative of the amount and direction of, as well as the presence of, registration error.

In a typical register error detector of the type which may be used with the print to cut register system of the present invention, photoelectric cell 70 provides an output signal in conductor 80 to coincidence circuit 81. The application of the photoelectric cell output signal to the coincidence circuit is controlled by a gate circuit 82 interposed in conductor 80. This gate circuit, shown diagrammatically in FIG. 1 as a switch, is controlled by the signal from switch 76 in conductor 84 so that for a certain time intervall during each cycle of operation of cutter press 22, gate circuit 82 is closed allowing the output signal of photoelectric cell 70 to be provided to coincidence circuit 81. This time interval is termed the scanning interval or scanning zone. The signal from switch 76 is also provided through a delay circuit 86, shown diagrammatically as a capacitor, to pulse generator 88 for causing the pulse generator to generate a pulse. The delay in the generation of the pulse by pulse generator 88 effected by delay circuit 86 is such that the pulse is provided halfway through the scanning zone.

The output signals of gate circuit 82 and pulse generator 88 are provided to coincidence circuit 81 which ascertains coincidence, or the lack thereof, between pulse generation by photoelectric cell 70 and by pulse generator 88. As indicated generally above, if the signal from photoelectric cell 70 and pulse generator 88 are generated simultaneously, no registration error exists between pattern 16 on web 14 and cutter press 22. If a registration error does exist in the cutter press, photoelectric cell 70 will generate a pulse either before or after the pulse provided by pulse generator 88. The precedence or sequence of the pulse from photoelectric cell 70 is taken as an indication of the direction of the registration error. For example, if the pulse from photoelectric cell 70 is generated before the pulse from pulse generator 88, the web is desired position due either to a position registration error or a repeat length error. If the pulse from photoelectric cell 70 is generated after the pulse from pulse generator 86, the web is behind the desired position.

The output signal of coincidence circuit 81 in conductor 90, is a bipolarity, variable duration signal. The polarity of the output signal is determined by the sequence of generation of the pulses by photoelectric cell 70 and pulse generator 88, and is thus an indication of the direction of the registration error. The duration of the error signal is proportional to the time difference between the generation of the two pulses and is thus an indication of the magnitude of the registration error. The output signal in conductor 90 from coincidence circuit 81 is supplied to the print to cut register system as hereinafter described, in the form of discrete pulses generated during each operation of the cutter press 22 which are indicative of the registration error existing in the cutter press during the immediately previous operation. The pulse signals control the operation of the print to cut register system to correct the registration error.

The output signal in conductor 90 is also provided to add/subtract circuit 92 which may in its simplest form be a capacitor. Add/subtract circuit 92 serves as an accumulator in that it sums each of the variable-duration pulse error signals generated in conductor 90 by coincidence circuit 81, as by adding a proportional charge to the capacitor. When the sum of a series of sequential error signals in conductor 90 reaches a predetermined magnitude (capacitor charge level), the circuit provides an output signal in conductor 94. This output signal is indicative of the fact that repetitive registration errors are appearing and that the additional corrective action by the print to cut register system is required.

An add/subtract circuit is employed to permit the occurrence of registration errors in one direction to be offset by the occurrence of registration errors in the other direction so that the cumulative error signal must be in a one of the two directions before an output signal is generated. The output signal from add/subtract circuit 92 in conductor 94 when the predetermined cumulative error signal magnitude is reached is a bipolarity pulse signal of a fixed time duration. The polarity of the output signal from add/subtract circuit 92 is an indication of the direction of the cumulative registration error between pattern 16 and cutter press 22. After generation of an output signal, add/subtract circuit 92 reverts to original condition and repeats its operation.

A register error detector suitable for use with the print to cut register system of the present invention is made and sold by Hurletron, lnc., Danville, "1., under the model designation 222-RB-.

The Gearbox and Differential Crankshaft 52 includes gearing 100 which drives main drive shaft 102. Drive shaft 102 provides power through gearbox 104 to shaft 106. The speed ratio between main drive shaft 102 and shaft 106 may be altered by the selection of the appropriate gears in gearbox 104 by means of lever 108. Shaft 106 comprises one of the two input shafts of differential 110. The output shaft 112 of differential 110 is connected through gearing 114 to continuously active metering feed roll 26. The gear ratio of gearbox 104 is selected so that, with the second input shaft to differential 110 locked, the metering feed rolls 26 and 28 are driven at a speed which provides, as closely as possible within the limits of the gear ratios of gearbox 104, the correct repeat length to web 14. It will be appreciated that replacable matched pairs of gears may be used instead of gearbox 104 to select the gear ratio, if desired.

The second input shaft to differential 110 is used to provide the alteration in metering feed roll speed necessary to establish and maintain registration between web pattern 16 and cutting die 46 of cutter press 22. This second differential input shaft is driven by the print to cut register system responsive to the output signals of the register error detector.

The Print to Cut Register System General The print to cut register system of the present invention is shown in block diagram form in FIG. 1 and in detailed schematic form in FIG. 2.

Conductors 90 and 94 containing the two output signals of the register error detector are connected to input terminals 120 and 122, respectively, of the print to cut register system. The print to cut register system includes a signal converting means for converting the fixed duration pulse signal provided to conductor 94 by add/subtract circuit 92 into a continuous signal having a magnitude responsive to the number of times such signals are generated. This means is illustratively shown in FIG. I as an electromechanical resolver 132 having a positioning motor 134 for adjusting the position of a movable winding in the resolver responsive to the signal in conductor 133 connected to terminal 122. The inductive coupling between the input and output portions of the resolver and the output signal in conductor 136 is altered by adjustment of the movable winding. The output signal of tachometer 124, responsive to the speed of web 14, is provided, through amplifier 126, in conductor 128 to input terminal 130 and through conductor 138 to resolver 132 so that the output of the resolver is also a function of the speed of the web. In this manner, when the speed of the web is altered, the operation of the print to cut register system is correspondingly altered so that the operation of the register system is coordinated with the speed of the web at all times. This is commonly termed tracking."

The system also includes a summation means for summing the continuous signal generated by the signal-converting means with the discrete registration error pulse signals in conductor 90, supplied through an input signal means 160, so as to provide an electric signal corresponding to the desired alteration in the rotary condition of the metering feed rolls 26 and 28. This means may typically be a summing amplifier 140, receiving as inputs, the signal in conductor 136 from resolver 132 and the signal in conductor 142 from terminal 120. An

output signal corresponding to the sum of the signals in the aforesaid conductors is provided at the output of amplifier in conductor 144.

The signal in conductor 144 is provided to a means for converting the electrical signal into a mechanical shaft speed, and direction signal. This means may comprise a feedback controlled servo amplifier 146 connected to conductor 144 and servomotor 148 operated by the servoamplifier.

A torque amplifier 150 is connected to servomotor 148 for amplifying the shaft speed, position, and rotary direction signal to a magnitude sufficient to permit its application to the second input shaft of differential 1 10 so as to provide a speed alteration to the metering feed rolls 26 and 28 necessary to correct the detected registration errors. A typical torque amplifier is the band and drum clutch assembly shown in FIGS. 1 and 2.

Input Signal Means Turning now to FIG. 2, the elements of one embodiment of the print to cut register system are shown in detailed schematic form therein. For purposes of illustration, an AC coupled system is shown therein in exemplary fashion.

Input signal means is interposed in conductor 142 between input terminal 120 and summing means 140 for converting the pulse signal in conductor 90 into AC signals suitable for operating the print to cut register system. For this purpose, the input signal means includes an AC power source comprised of a transformer 162, the primary winding 164 of which is connected to an alternating current power supply (not shown) and the secondary winding 166 of which has a grounded center tap. One end of secondary winding 166 is connected through parallel relay contacts 168a and 170a to conductor 142a. The other end of secondary winding 166 is also connected through parallel relay contacts 172a and 1740 to conductor 142a.

Relay contacts 168a and 172a are operated by relay coils 168b and 172k connected to conductor 142 and energized by the pulse signals from coincidence circuit 81. Oppositely poled diodes 176 and 178 are connected in series with the relay coils so that a pulse signal of one polarity from coincidence circuit 81 energizes one of the relay coils while a pulse signal of the other polarity energizes the other of the relay coils.

When closed by the energization of relay coil 168b, relay contacts 168a provide an AC signal in conductor 142a having a phase which is opposite that of the AC signal provided in conductor 142a when relay contacts 172a are closed by the energization of relay coil 172b, as shown by the AC graphs 176a and b adjacent the opposite ends of transformer secondary winding 166. Thus, input signal means 160 converts the bipolarity pulse signals in conductor 90 into corresponding AC pulse signals, the phase of which is controlled by the polarity of the pulse signals from coincidence circuit 81.

A manual control is included in input signal means 160 to provide for the generation of signals in conductor 142a independently of the pulse signals from coincidence circuit 81. This manual control has a signal source, such as grounded center tap batter 178 having a manually manipulatable switch 180 connectable to either end of the battery. The signal from switch 180 is provided in conductor 182 to parallel connected relay coils 1701; and 174k for opening and closing relay contacts 170a and 174a, respectively. Oppositely poled diodes 184 and 186 inserted in series with the relay coils causes one polarity of voltage in conductor 182 to energize one of the relay coils and the other polarity of voltage in conductor 182 to energize the other relay coil. Relay contacts 170a and 174a provide oppositely phased AC voltages in conductor 142a in a manner similar to relay contacts 168a and 172a. If desired, the signal level provided by relay contacts 168a and 1720 in conductor 142a may be rendered different, as by resistors 188 and 190.

As will hereinafter be described in greater detail, signals generated in conductor 142a by the closure of relay contacts 168a and 170a serve to advance the position of web pattern 16 with respect to cutting die 46 so that these relay contacts are given an advance designation ADV in FIG. 2. Relay contacts 1680 are designated as the automatic advance contacts AUTO ADV, to indicate that their operation is governed by the operation of the register error detector in an automatic manner whereas relay contacts 170a are designed MAN ADV to indicate their operation is manually controlled by switch 100.

The closure of relay contacts 172a and 174a generate signals which serve to retard the position of web pattern 16 with respect to cutting die 46 so that these contacts are designated AUTO RET and MAN RET, respectively, for reasons analogous to the designation of contacts 168a and 170a.

Turning now to the other output signal of the register error detector, that is, the fixed duration pulse output signal in conductor 94 from add/subtract circuit 92, this signal may be supplied directly to resolver positioning motor 134 in conductor 133, assuming motor 134 is of a direct current type. If motor 134 is of an alternating current type, an input signal means, similar to input signal means 160, must be utilized.

A selector switch 200 is interposed in conductor 133 to select either manual or automatic operation of motor 134. In the automatic position of selector switch 200, motor 134 is connected directly to input terminal 122 and its operation is automatically controlled by the register error detector. In the manual position of selector switch 200, motor 134 is connected to switch 202 operatively associated with grounded center tap battery 204 so that motor 134 may be rotated in either direction by manual manipulation of switch 202.

THE COMPUTING RESOLVER As hereinbefore noted, the signal-converting means incorporated in the print to cut register system of the present invention for converting the fixed duration pulse signals of and/subtract circuit 92 into a continuous signal, may comprise a computing resolver. A resolver is a single phase transformer, the secondary winding of which is relatively rotatable with respect to the field of the primary winding. The secondary winding is generally mounted on a rotor and is movable from a position in which it is alignment with the poles of the stator field, and thus has a maximum voltage induced therein, to a position in which it is across the magnetic field of the stator and has a minimum voltage induced therein. The magnitude of the induced voltage is a function of the primary or stator winding energization, as well as the rotor position, so that an output voltage or signal taken from the secondary winding is the function of the two factors. The position of the rotor also determines the phase relationship of the induced output voltage with respect to the voltage applied to the primary winding. In the present print to cut register system, the output voltage of the resolver is used to provide registration correction in accordance with both the magnitude and the phase of the resolver output voltage in a manner hereinafter described.

The computing resolver 132 incorporated in the print to cut register system of the present invention is shown in diagrammatic form in FIG. 2 to facilitate the analysis of its operation. Computing resolver 132 includes a primary or stator winding 206 energized by the signal in conductor 138 from tachometer 124 responsive to the speed of web 14. It will be appreciated that the primary winding energizing signal from tachometer 124 includes the alternating circuit bias necessary for the transformer operation of resolver 132.

The secondary, or rotor, winding 208 of resolver 132 is mounted on rotor shaft 210 so that the winding may be rotated within the magnetic field created by stator winding 206 by resolver positioning motor 134. The winding may be placed on magnetic core 212. A pair of slip rings 214 and 216 are provided on rotor shaft 210 to which the ends of rotor winding 208 are connected and from which the output signal of computing resolver 132 is taken by brushes 210 and 220. The output signal from brushes 218 and 220 is provided in conductor 136.

There are numerous computing resolvers presently on the market which are suitable for use as resolver 132. For example, the resolver manufactured by Clifton Precision Products Corporation, 8 Progress Parkway, Maryland Heights, Mo., and sold under the model designation CSHl5DS3, may be used.

Rotor shaft 210 is rotated by resolver positioning motor 134 which may be any of the various types of commercially available motors capable of providing closely controlled rotation to rotor shaft 210. A low speed motor, such as a l r.p.m. motor is suitable for use as positioning motor 134.

A pulse signal of one polarity in conductor 133 from add/subtract circuit 92 causes the motor 134 to turn in one direction, while a pulse signal of the other polarity cause the motor to turn in the other direction. As the output signal from add/subtract circuit 92 in conductors 94 and 133 is a pulse signal of fixed duration, motor 134 is likewise rotated a constant amount each time it is energized. In a similar manner, when selector switch 200 is in the manual position, motor 134 will be rotated in a direction determined by the polarity of the signal generated in switch 202 from battery 204. The amount of rotation of motor 134 is determined by the closure time of switch 202.

When rotor winding 208 is rotated in one direction from the null, or minimum voltage, position of the rotor winding, an AC signal of a given phase will be generated in conductor 136. The magnitude of the AC signal will be proportional to the amount of rotation from the null position. When the rotor winding is rotated in the other direction from the null position, an AC signal of the opposite phase will be generated in conductor 136. The magnitude of this AC signal will also be proportional to the amount of rotation. One phase of the AC signal occuring in the print to cut register system may hereinafter be designated as positive phase while the other, opposite phase is termed the negative phase, as by reference to the AC half-cycle which occurs immediately after a time base point.

In order to maintain linearity between the change in position of secondary winding 208 and the change in magnitude of the output signal in conductor 130, the rotation of output shaft 210 on either side of the null, or minimum voltage, position of the rotor winding 208 with respect to stator winding 206 may be limited. For this purpose, a cam 222 is mounted on rotor shaft 210 for actuating limit switches 224 and 226 to shut down motor 134, as by opening switch 220 when the predetermined limits of rotation are reached. It has been found that sufiicient linearity or proportionality between the change in position of rotor winding 208 and the output signal in conductor 136 may be obtained by limiting the rotation of rotor shaft 210 to between 30 and 60 on either side of the null position of rotor winding 208.

To ascertain the rotary position of rotor core 212 and secondary winding 208 with respect to the magnetic field of primary winding 206, an indicator disc 211 may be provided on rotor shaft 210. Disc 211 has a scale 213 which cooperates with index line 215 for locating the resolver rotor. Scale 213 and index line 215 are located so that a reading of zero is obtained when the rotor winding 208 is in the null position. Scale 213 may be calibrated on either side of the zero position in inches of increase or decrease in the repeat length of web 14 obtained by altering the position of secondary winding 208. This allows the position of secondary winding 200 to be preset prior to the operation of web-treating apparatus 10 so as to compensate for known repeat length errors, in a manner hereinafter described.

As a result of the above-described interconnection and operation of resolver 132, a continuous AC output signal is generated in secondary winding 200 and conductor 136, the magnitude of which is a function both of the speed of web 14,

because of the energization of the primary winding 206 by tachometer 124, and the output signal of the register error detector in conductor 90 from add/subtract circuit 92, because of the rotation of secondary winding 208 responsive to this latter signal. The phase of the continuous AC output signal is a function of the direction of rotation of rotor winding 208 from the null position and therefore a function of the polarity of the output signal of the register error detector in conductor 94.

The Summing Means The signal from resolver secondary winding 208 in conductor 136 and the signal from coincidence circuit 81 in conductor 142 are supplied to the input of a summing means, capable of summing the biphase AC signals existing in the conductors. This may, for example, be operational amplifier 140. An output signal corresponding to the sum of the signals in the aforesaid conductors is provided at the output of amplifier 140 in conductor 144. The output signal is an AC signal, the magnitude and phase of which is a function of the relative magnitudes and phases of the AC input signals in conductors 136 and 142a. Input signals of similar phases are added while input signals of different phases are subtracted. The output signal corresponds to the alteration to be effected in the rotary condition of the metering feed rolls 26 and 28 by the print to cut register system to correct the registration error between web pattern 16 and cutting die 46.

The Servomotor The output signal in conductor 144 is provided to servo amplifier 146 and thence to servomotor 148 by means of conductor 230. Servomotor 148 converts the output signal of amplifier 140 into the shaft speed and rotary direction signal necessary to actually effect the desired alteration in the rotary condition of metering feed rolls 26 and 28. The servomotor shaft signal is amplified, as hereinafter described, and applied to the metering feed rolls to effect the required correction.

Servomotor 148 may be of the type having a pair of electrically displaced stator windings 232 and 234. One of the stator windings 234 may be biased with alternating current from source 236 to create a magnetic field in the servomotor. The other stator winding 232 may be energized by the output signal in conductor 230 from amplifier 146, so as to create a revolving magnetic field in the servomotor to cause the motor to rotate in accordance with the energization of stator winding 232. The direction in which the output shaft 238 of servomotor 148 will rotate is determined by the phase of the output signals in conductor 230, the speed at which it rotates depends on the magnitude of the output signal, and the amount by which it rotates depends on the duration of the output signal. A tachometer 240 on the output shaft 238 of servomotor 148 provides a feedback signal to servo amplifier 146 to insure that the output of servomotor 148 corresponds to the input signal from amplifier 146.

Torque Amplifier 150 in the form of a motor 242. The application of the power of motor 242 to output shaft 244 of torque amplifier 150 is controlled by the output shaft of servomotor 148, thereby achieving the described torque amplification. Motor 242 drives input shaft 246 of torque amplifier 150 which in turn drives a pair of drums 248 and 250 in opposite directions through gearing 252.

A spiral, or helical, band surrounds each of the drums. Specifically, band 254 surrounds drum 248 while band 256 surrounds drum 250. One end of each of the bands is connected through gearing 258 to output shaft 244. The other end of the bands is connected to gearing 260 which is coupled to output shaft 238 of servomotor 148 in a manner such that rotation of the output shaft of servomotor 148 serves to tighten one or the other of the bands onto the respective drum so as to couple output shaft 244 to one of the drums driven by input shaft 246. The direction in which the servomotor output shaft 238 rotates determines which of the drums will be coupled to the output shaft and the direction of rotation of output shaft 244. The speed at which the servomotor output shaft 238 rotates determines the amount of the clutching action between the band and the drum and thus the speed of output shaft 244. in this manner the speed and direction characteristics of the output shaft 238 of servomotor 148 undergo a power magnification.

The output shaft 244 of torque amplifier 150 comprises the second input of differential 110.

A torque amplifier of the general type described above is made and sold by the Seneca Falls Machine Company, Seneca Falls, N.Y., under the description Mechanical Power Amplifier and model designation Mark IV or V. See also US. Pat. No. 3,187,599 to Eisengrein, et al., assigned to the aforementioned Seneca Falls Machine Company.

Operation of Web-Treating Apparatus In considering the general operation of web-treating apparatus 10, it may be assumed that web 14 is being reeled off unwind stand 12 at a relatively uniform rate by an unwind stand drive mechanism or drive rolls (not shown). The web passes through continuously active metering feed rolls 26 and 28 which, in turn, meter the web to cutting press 22 at a precise rate.

During each cycle of operation of cutter press 22, as cutting die 46 moves away from platen 40, brake bars 30 and 32 release web 14. At the same time intermittently active feed rolls 34 and 36 engage web 14 to move the entire slack loop 14a of the web into the cutter press. As cutting die 46 again moves toward platen 40, brake bars 30 and 32 reengage the web and intermittently active feed rolls disengage the web so that the portion of the web in the press is stationary as cutting die 46 cuts the web against platen 40. Continuously active feed rolls 26 and 28 reform the slack loop 24a by feeding an additional repeat length of web material into the loop during the time brake bars 30 and 32 engage web 14.

Operation of the Print to Cut Register System Turning now to consideration of the print to cut register system of the present invention, it may be further assumed that during the immediately preceding operative cycles of cutter press 22, no register error has been detected between web pattern 16 and cutting die 46. Metering rolls 26 and 28 are driven by gearbox 104 and differential 110 at a speed which feeds, as closely as possible, within the gear ratios of gearbox 104, the desired repeat length into slack loop 14a during each operation of cutter press 22.

As no registration error exists between pattern 16 on web 14 and cutter press 22, none will be detected by the registration error detector. The pulse generated by photoelectric cell 70 and the pulse generated by pulse generator 88 will arrive at coincidence circuit 81 coincidentally. Because of the synchronism in pulse generation, no output signal will be provided in conductors 90 and 94 which would alter the operation of the print to cut register system.

Tachometer 124 energizes primary winding 206 of resolver 132 with a signal proportional to the speed of web 14. The secondary winding 208 of resolver 132 remains in the position, with respect to the magnetic field of energized primary winding 206, established by the previous operations of the print to cut register system. A continuous signal is therefore generated in conductor 136, the magnitude of which is a function of the speed of web 14, through the energization of primary winding 206, and the relative position of secondary winding 208 with respect to the magnetic field of the primary winding. The phase of this signal is also a function of the relative position of secondary winding 208 with respect to the magnetic field of the primary winding and specifically the direction of rotation of the secondary winding from the null position. The signal in conductor 136 is shown by the graph 306 in FIG. 2 as a positive phase signal.

The continuous signal in conductor 136 is provided to summing amplifier 140. As the register error detector is in the quiescent state, no signal is generated in conductor 90 and none is supplied via conductors 142 and 142a, to summing amplifier 140 so that the signal in conductor 136 from computing resolver 132 is the only signal received by summing amplifier 140. The output signal of summing amplifier 140 in conductor 144 is therefore an AC signal proportional in magnitude, and corresponding to phase to the signal in conductor 136 and is designated by the same graph and number.

The output signal of summing amplifier 140 is provided to servomotor 148, through servoamplifier 146, to energize stator winding 232 of the servomotor to cause servomotor output shaft 238 to rotate in a direction and at a speed determined by the phase and magnitude, respectively, of the output signal 306 of summing amplifier 140.

The shaft speed and direction signal of servomotor 148 is supplied to torque amplifier 150 through gearing 260 which causes one of the bands of torque amplifier 150 to tighten on one of the drums, thereby to drive output shaft 244 at a speed and in a direction similar to the speed and direction of servomotor output shaft 238.

Output shaft 244 of torque amplifier 150 is connected to the second input of differential l so that the rotary speed condition of continuously active metering feed rolls 26 and 28 is a summation of the speed of shaft 106 from gearbox 104 and the speed of output shaft 244 of the torque amplifier 150 in the print to cut register system. The speed of shaft 244 may be either additive or subtractive of the speed of shaft 106 in determining the speed of metering rolls 26 and 28, depending on the relative directions of rotation of the two shafts. In the present exemplary case, it will be assumed that the speed of shaft 244 is additive to the speed of shaft 106 so that the summed total of the speeds of the two shafts is such as to rotate continuously active metering feed rolls 26 and 28 at a speed which maintains the registration between web pattern 16 and cutter press 22.

It is theoretically possible to drive metering feed rolls 26 and 28 solely by means of gearbox 104 at a speed sufficient to maintain registration, as by selecting gear ratios for gearbox 104 and roll diameters for metering feed rolls 26 and 28 which will meter exactly the right repeat length of web 14 into the slack loop 14a during each operation of the cutter press 22. However, as a practical matter this is difficult, if not impossible. Due to slippage between the web and the rolls, stretching of the web, and the like, registration errors inevitably occur no matter how carefully the gear ratios and roll diameters are selected. These errors necessitate almost continual utilization of the print to cut register system to maintain registration and the web-treating apparatus 10 has been so described, supra.

When a registration error does appear in the position of pattern 16 with respect to cutting die 46, of either the positional type or repeat length type, during any given operative cycle of cutter press 22, the following occurs. The registration error detector detects the registration error and an output signal is provided in conductor 90 to terminal 120 of the print to cut register system. The time length or duration signal is proportional to the magnitude of the registration error and the polarity of the signal is in accordance with the direction of the sensed registration error. In an exemplary case, the registration error detector may ascertain that the pattern 16 on web 14 is ahead of the desired position with respect to cutting die 46 by 0.1 inch and provide a signal of negative polarity for 0.1

seconds in conductor 90. This signal is diagrammatically shown in FIG. 3 by the graph 302. It may also be assumed that the accumulated error must total 0.5 inch in one direction before an output signal is provided from add/subtract circuit 92 in conductor 94. Thus, at the present time, no output signal is provided in conductor 94.

The signal 302 in conductor is supplied through terminal to conductor 142 to energize input signal means 160. Signal 202, being of the negative polarity, energizes relay coil 172b to close relay contacts 172a, as shown in FIG. 3, and generate an AC signal 304 in conductor 1420 from transformer secondary winding 166. The AC signal 304 is generated for the 0.1 second that signal 302 in conductor 142 from coincidence circuit 81 energizes relay coil 172b, The phase of signal 304 is negative, which is indicative of the fact that signal 302 is of a negative polarity. Signal 304 is supplied to the input of summing amplifier in conductor 1420.

As no signal is provided in conductor 94. the operation of resolver 132 is not altered from that obtained during the previous operation of cutter press 22 during which no registration error was detected. Positive phase signal 306 continues to be generated in conductor 136. As noted supra, the magnitude of signal 306 is a function of the speed of web 14 and the position of rotor secondary winding 208 and the phase of signal 306 is a function of the direction of rotation of rotor winding 208 with respect to the null position of the winding. Signal 306 is supplied by conductor 136 to the input of summing amplifier 140.

Summing amplifier I40 sums input signal 304 in conductor 142a and input signal 306 in conductor 136 and provides an output signal accordingly. As the phases of signals 304 and 306 are opposite, signal 304 will be subtracted from signal 306 to produce signal 308 in conductor 144. As noted from FIG. 3, signal 308 includes reduced signal 308a, the magnitude of which represents the difference in magnitudes between signal 306 and 304. Signal 308a corresponds to the reduction in the rotary speed of continuously active metering feed rolls which must be made to move web pattern 16 backward with respect cutting die 46 and into registration with the die.

Signal 308 is applied to servomotor 148, through servoamplifier 146, to reduce the speed of servomotor output shaft 238 in accordance with reduced signal portion 308a; that is, to reduce the speed of servomotor output shaft 238 in proportion to the reduced magnitude of signal portion 308a and for the 0.1 second time interval during which signal portion 308a is formed by the subtraction of signal 304 from signal 306.

The reduction in the speed of servomotor output shaft 238 reduces the speed of torque amplifier output shaft 244 by a like amount and for a like time interval. This reduces the speed of continuously active metering feed rolls 26 and 28 correspondingly through differential 110 so as to decrease the length of web 14 supplied to slack loop 14a by the metering rolls preparatory to the next operative cycle of cutter press 22.

It may well be that the reduced length of material in slack loop 14a which is supplied to cutter press 22 during the next cycle of operation will be such as to move the web pattern rearward to a position in which it is in exact registration with cutting die 46. This is often the case when the registration error is of the positional type. If registration is obtained, the registration error is of the positional type. If registration is obtained, the registration error detector ascertains the condition of registration and no output signal is provided in conductor 90 during the subsequent operations of cutter press 22. The signal recorded in add/subtract counter 92 remains entered there, however.

In many cases, a registration error will still remain between pattern 16 on web 14 and cutting die 46 of cutter press 22. This may occur when the registration error is of the repeat length type. For example, the repeat length of web supplied by metering rolls 26 and 28 when driven by gearbox 104 alone, may be 0.1 inch too great. Thus, while the positional pattern of web 14 will be moved 0.1 inch rearwardly by the reduced repeat length of web 14 supplied by the above described operation of the print to cut register system, the excessive repeat length reinserts the same registration error on the subsequent cycle of operation of cutter press 22. The registration error detector detects the same 0.1-inch error and the print to cut register system provides the same rotary condition correction to feed rolls 26 and 28. The additional 0.1-inch correction is noted by add/subtract counter 92 and added to the 0.1 inch recorded therein from the previous operation.

If the registration error is due to improper repeat lengths resulting from the inability of gearbox 104 and the print to cut register system to drive feed rolls 26 and 28 at the precise speed needed to provide the correct repeat length in slack loop 14a, a registration error will continue to appear during each cycle of operation of cutter press 22. In the present exemplary instance, when the cutter press has operated five times with the registration error of 0.1 inch, a total of 0.5-inch error will have been accumulated in add/subtract counter 92. At this point, add/subtract counter 92 has reached its preset maximum of 0.5 inch of registration error and provides an output signal 310 of a predetermined duration in conductor 94 as shown in FIG. 4. For example, the duration of signal 310 may be 0.3 seconds. The polarity of signal 310 is negative as the accumulated error is the sum of a series of errors in which the web pattern 14 is ahead of the desired position with respect to cutting die 46.

Signal 310 is provided through conductor 94 to input terminal 122 of the print to cut register system and to conductor 133. Assuming selector switch 200 is in the automatic position, the signal in conductor 133 is supplied to resolver-positioning motor 134, energizing the motor to rotate resolver shaft 210 and secondary winding 208. In the present example, motor 134 will move secondary winding 208 toward the null position so as to provide a reduced continuous output signal 312 in conductor 136. Because of the linearity or proportionality between the rotor winding position and the induced voltage in the rotor winding 208, the change in the output signal of resolver 132 in conductor 136 is proportional to the amount of displacement of rotor winding 208.

Reduced output signal 312 is provided to summing amplifier 140 and to servomotor 148 to reduce the speed of servomotor output shaft 238 on a continuous basis to a lower level. The reduction in speed of output shaft 238 causes a corresponding reduction in the speed of torque amplifier output shaft 244 and in the speed of continuously active metering feed rolls 26 and 28. The reduction in the speed of the continuously active metering feed rolls decreases the repeat length 14a of the web 14 and serves to move web pattern 16 rearwardly with respect to cutting die 46 and into registration with the cutting die for all succeeding operations of cutter press 22. As registration errors reoccur in web-treating apparatus 10 they are corrected in the same manner as described above.

From the foregoing, it will be readily appreciated that registration errors caused by the position of web pattern 16 being behind the position necessary for registration with cutting die 46, rather than ahead of such a position as in the examples above, are corrected by increasing the speed of feed rolls 26 and 28, and the repeat length of web 14, either for a single operation of cutter press 22 responsive to a signal from coincidence circuit 81 or continuously responsive to a signal from add/subtract circuit 92.

It will be further appreciated that, in instances in which the registration errors are occurring at random, that is, first in one relative direction of web pattern 16 with respect to cutting die 46 and then in the other relative direction, errors in one direction are subtracted from errors in the other direction in add/subtract counter 92 so as to insure that only when the registration error repeatedly occurs in the one direction is an output signal provided in conductor 94.

In the event the repetitive operation of cutter press 22 is speeded up, continuously active metering feed rolls 26 and 28 will be driven faster by gearing 100 connected to crankshaft 52, gearbox 104, and differential 110 so as to supply the same repeat length of web 14 to slack loop 14a during each cycle of operation even though a shorter time interval is available for so doing.

The corrections for registration errors made by print to cut register system 10 must also be made more rapidly under such conditions because of the shortened time interval. As the operation of cutter press 22 is increased, the line speed of web 14 is likewise increased. This causes tachometer 124 to provide an increased output signal through amplifier 126 and conductors 128 and 138 to resolver primary winding 206 so as to correspondingly increase the magnitude of any output signal induced in resolver secondary winding 208 and provide more rapid correction through servomotor 148 and torque amplifier 150 for registration errors appearing between pattern l6 and cutting die 46.

In many cases, the magnitude of expected registration errors may be determined to a greater or lesser extent prior to the operation of cutter press 22. It is therefore desirable to correct the registration errors before cutter press 22 is run to lessen wastage of the web due to incorrect registration.

For example, if it is clearly evident that the repeat length of web 14 provided by continuously active metering feed rolls when rotated through differential by gearbox 104 alone is 0.1 inch longer than the length required for registration, selector switch 200 may be switched to the manual position. Switch 202 is then manipulated to provide a signal from battery 204 to resolver positioning motor 134 to rotate resolver rotor winding 208. Through the operation of the print to cut register system, this will alter the speed and rotary direction of output shaft 244 of torque amplifier so as to reduce the speed of feed rolls 26 and 28 by the amount necessary to reduce the repeat length of the web 0.1 inch to the proper length.

As noted supra, because of the proportionality maintained between changes in the position of rotor winding 208 and changes in the magnitude of the resolver output in conductor 136, disc 211 which indicates the rotary position of resolver secondary winding 208 may be calibrated directly in inches of increase or decrease in the repeat length of web 14 obtained by altering the position of secondary winding 208. Similarly, if it is evident that, while the web repeat length is correct, the position of pattern 16, with respect to cutting die 46, is incorrect, the switch 180 in input signal means may be manipulated to energize one of relay coils b or l74b to close relay contacts 170a or 1740 to generate a signal in conductor 142a. The signal provided to summing amplifier 140 from input signal means 160 under such conditions operates the print to cut register system in a manner similar to a signal from coincidence circuit 81 produced during actual operation of cutter press 22 to alter the position of web pattern 16 with respect to cutting die 46.

Other Embodiments Other forms and embodiments of the print to cut register system described above may be devised. For example, rotary transformer or resolver 132 may be replaced by a linear transformer 132a shown in FIG 5A. Such linear transformers typically have the primary winding 206a and secondary winding 208a thereof coupled through a rectilinearly movable core 209 so that by moving the core the coupling is varied. The core may be moved by a lead screw mechanism 231 connected to motor 134.

If it is desired to use direct current control signals, rather than AC signals in the print to cut register system of the present invention, a slide wire resistor arrangement 132b may be utilized in which the resistive element or wire 206b is energized by a direct current tachometer 124a responsive to web speed. The resistor slide 208b, from which the output signal for conductor 136 is taken, is driven by motor 134 through a leadscrew arrangement 231a. See FIG. 5B.

If it is desired to avoid the use of electromechanical devices, a step function generator 1320 as shown in FIG. 5C may be utilized. Such a function generator provides a plurality of output signal levels responsive to a series of input signals. The output signal levels may be either AC or DC as desired. The polarity of the input signals and of the output signal level may correspond. As the number of input signals of a given polarity received by function generator 132a increases, the output signal level also increases.

in the present print to cut register system such a function generator may be employed to provide an increasing output signal level 316 in conductor 136 as the number of output signals 310 of a given polarity from add/subtract circuit 92 increases. Subsequently received output signals from add/subtract circuit 92 of the other polarity would reduce the signal level or reverse its polarity if they exceeded, in number, the number of output signals of the given polarity.

Tachometer 124 may also be connected to function generator 1320 by conductor 138 to uniformly increase all the output signal levels as the speed of the web increases. Coincidence circuit 81 may also be connected to the function generator by conductor 14120 to momentarily alter the signal level responsive to the coincidence circuit output signals thus combining the converting and summing means.

The converting means and summing means may also be combined, in resolver 132d shown in FIG. D, through the use of an additional primary winding 2060. This winding is mounted on rotor core 212 and energized through brushes 225 and 227 and collector rings 219 and 221 with the signal in conductor 142a from coincidence circuit 81. The signal from coincidence circuit 81 would then be electromagnetically added to the signal induced in secondary winding 208 by the energization of primary winding 206 and the relative position of the rotor winding with respect to the stator field and provided in conductor 136 directly to servoamplifier 146.

lclaim:

l. A registration system for providing registration between successive portions of a moving web and a web-treating apparatus cyclically applied to each of the web portions, said web-treating apparatus having controllable metering rolls located upstream along the web for regulating the length of the web portion provided to the web treating apparatus during each cycle of operation and the registration of the portions with the apparatus in accordance with the rotary condition of the rolls, said web-treating apparatus further having a registration error detector for detaching the registration error between the web-treating apparatus and the successive portions of the web and providing an error signal accordingly, said web-treating apparatus having a differential drive means for establishing a rotary condition of the metering rolls, said registration system comprising:

a signal-converting means having an input responsive to the error signal of the registration error detector for converting the error signal into an output signal corresponding to a registration-correcting alteration in the rotary condition of the metering rolls;

said registration error detector providing a periodic error signal in accordance with a predetermined cumulative registration error occurring over sequential cycles of operation of the web-treating apparatus and wherein said signal converting means comprises means for converting the periodic error signal into a continuous output signal responsive to the occurrence of the error signal,

said signal-converting means also including a signalgenerating means for providing a signal and a signal-altering means cooperable therewith, said signal-altering means containing said signal-converting means input and being operable by the error signal for altering the signalgenerating means signal to convert the error signal into said output signal, said signal-altering means being electromechanically cooperable with said signal-generating means and said signal-altering means being mechanically movable responsive to the error signal for altering the signal-generating means signal, and

electromechanical means coupled to said signal-converting means and having a controllable output member responsive to said output signal, said output member being drivingly connected to the differential drive means for altering the rotary condition of the metering rolls to provide registration between the web portions and the webtreating apparatus.

2. The registration system according to claim 1 wherein said signal-generating means comprises a secondary circuit inductively coupled to a primary circuit for providing the output signal in said secondary circuit, and said signaLaltering means comprises means for varying the inductive coupling between said primary and secondary circuits by means of mechanical motion.

3. The registration system according to claim 2 wherein said signal-altering means comprises means for rotating said secondary circuit with respect to said primary circuit to vary the inductive coupling between the primary and secondary circuits.

4. The registration system according to claim 3 wherein said signal-altering means includes means for limiting the relative rotation of said secondary circuit and the variability of the inductive coupling to preselected limits.

5. The registration system according to claim 2 wherein said primary and secondary circuits are inductively coupled through a movable magnetic core and wherein said signalaltering means includes means for moving said magnetic core to vary the coupling between said primary and secondary circuits.

6. The registration system according to claim 1 wherein said signal-generating means comprises a resistive element having a wiper providing said output signal and said signal-altering means comprises means for moving said wiper with respect to said resistive element.

7. The registration system according to claim 1 including means for generating an output signal from said signal converting means independently of the registration error detector error signal.

8. The registration system according to claim 1 including means for mechanically moving said signal-altering means in dependently of the registration error detector error signal.

9. The registration system according to claim 1 wherein said signal-converting means comprises electronic means for providing a continuous output signal responsive to the occurrence of the error signal.

10. The registration system according to claim 1 wherein the web-treating apparatus includes a registration error detector providing an additional error signal corresponding to the registration error existing during each cycle of operation and wherein said registration system includes a summing means having an input receiving the additional error signal and said output signal of said signal-converting means and providing an electric signal corresponding to the sum of the additional error signal and said output signal and wherein said electromechanical means is responsive to said electric signal.

11. The registration system according to claim 10 wherein said summing means comprises electronic summing means.

12. The registration system according to claim 10 wherein said summing means comprises means for inductively summing the additional error signal and said output signal.

13. The registration system according to claim 10 including means connected to said summing means for altering said summed electric signal independently of the registration error detector and the signal converting means.

14. The registration system according to claim 1 wherein said electromechanical means includes a servomotor having a rotatable output shaft coupled to the differential drive means, said servomotor having an energizablie electromagnetic circuit determinative of the rotary condition of said output shaft, said electromagnetic circuit being energized by the electric signal for determining the rotary condition of the output shaft.

15. The registration system according to claim 1 wherein said electromechanical means includes a torque amplifier interposed between the output shaft of said servomotor and said differential drive means and containing said output member, said torque amplifier amplifying the rotary condition of said servomotor output shaft.

16. The registration system according to claim wherein said torque amplifier includes a primary power source independent of said differential drive means.

17. A registration system for providing registration between successive portions of a moving web and a web-treating apparatus cyclically applied to each of the web portions, said web-treating apparatus having controllable metering rolls located upstream along the web for regulating the length of the web portion provided to the web-treating apparatus during each cycle of operation and the registration of the portions with the apparatus in accordance with the rotary condition of the rolls, said web-treating apparatus further having a registration error detector for detecting the registration error between the web-treating apparatus and the successive portions of the web and providing an error signal accordingly, said web-treating apparatus having a differential drive means for establishing a rotary condition of the metering rolls, said registration system comprising:

a signal-converting means having an input responsive to the error signal of the registration error detector for converting the error signal into an output signal corresponding to a registration correcting alteration in the rotary condition of the metering rolls; said registration error detector providing a periodic error signal in accordance with a predetermined cumulative registration error occurring over sequential cycles of operation of the web-treating apparatus and wherein said signal-converting means comprises means for converting the periodic error signal into a continuous output signal responsive to the occurrence of the error signal, said signal-converting means includes a signal-generating means for providing a signal and a signal-altering means cooperable therewith, said signalaltering means containing said signal-converting means input and being operable by the error signal for altering the signal-generating means signal to convert the error signal into said output signal, a tachometer for measuring the speed of the moving web and for providing a speed signal proportional to the speed of the web and wherein said signal-generating means is energized by the speed signal of said tachometer, and electromechanical means coupled to said signal converting means and having a controllable output member responsive to said output signal, said output member being drivingly connected to the differential drive means for altering the rotary condition of the metering rolls to provide registration between the web portions and the web-treating apparatus. 

1. A registration system for providing registration between successive portions of a moving web and a web-treating apparatus cyclically applied to each of the web portions, said web-treating apparatus having controllable metering rolls located upstream along the web for regulating the length of the web portion provided to the web treating apparatus during each cycle of operation and the registration of the portions with the apparatus in accordance with the rotary condition of the rolls, said web-treating apparatus further having a registration error detector for detaching the registration error between the web-treating apparatus and the successive portions of the web and providing an error signal accordingly, said web-treating apparatus having a differential drive means for establishing a rotary condition of the metering rolls, said registration system comprising: a signal-converting means having an input responsive to the error signal of the registration error detector for converting the error signal into an output signal corresponding to a registration-correcting alteration in the rotary condition of the metering rolls; said registration error detector providing a periodic error signal in accordance with a predetermined cumulative registration error occurring over sequential cycles of operation of the web-treating apparatus and wherein said signal converting means comprises means for converting the periodic error signal into a continuous output signal responsive to the occurrence of the error signal, said signal-converting means also including a signal-generating means for providing a signal and a signal-altering means cooperable therewith, said signal-altering means containing said signal-converting means input and being operable by the error signal for altering the signal-generating means signal to convert the error signal into said output signal, said signal-altering means being electromechanically cooperable with said signal-generating means and said signal-altering means being mechanically movable responsive to the error signal for altering the signal-generating means signal, and electromechanical means coupled to said signal-converting means and having a controllable output member responsive to said output signal, said output member being drivingly connected to the differential drive means for altering the rotary condition of the metering rolls to provide registration between the web portions and the web-treating apparatus.
 2. The registration system according to claim 1 wherein said signal-generating means comprises a secondary circuit inductively coupled to a primary circuit for providing the output signal in said secondary circuit, and said signal-altering means comprises means for varying the inductive coupling between said primary and secondary circuits by means of mechanical motion.
 3. The registration system according to claim 2 wherein said signal-altering means comprises means for rotating said secondary circuit with respect to said primary circuit to vary the inductive coupling between the primary and secondary circuits.
 4. The registration system according to claim 3 wherein said signal-altering means includes means for limiting the relative rotation of said secondary circuit and the variability of the inductive coupling to preselected limits.
 5. The registration system according to claim 2 wherein said primary and secondary circuits are inductively coupled through a movable magnetic core and wherein said signal-altering means includes means for moving said magnetic core to vary the coupling between said primary and secondary circuits.
 6. The registration system according to claim 1 wherein said signal-generating means comprises a resistive element having a wiper providing said output signal and said signal-altering means comprises means for moving said wiper with respect to said resistive element.
 7. The registration system according to claim 1 including means for generating an output signal from said signal converting means independently of the registration error detector error signal.
 8. The registration system according to claim 1 including means for mechanically moving said signal-altering means independently of the registration error detector error signal.
 9. The registration system according to claim 1 wherein said signal-converting means comprises electronic means for providing a continuous output signal responsive to the occurrence of the error signal.
 10. The registration system according to claim 1 wherein the web-treating apparatus includes a registration error detector providing an additional error signal corresponding to the registration error existing during each cycle of operation and wherein said registration system includes a summing means having an input receiving the additional error signal and said output signal of said signal-converting means and providing an electric signal corresponding to the sum of the additional error signal and said output signal and wherein said electromechanical means is responsive to said electric signal.
 11. The registration system according to claim 10 wherein said summing means comprises electronic summing means.
 12. The registration system according to claim 10 wherein said summing means comprises means for inductively summing the additional error signal and said output signal.
 13. The registration system according to claim 10 including means connected to said summing means for altering said summed electric signal independently of the registration error deteCtor and the signal converting means.
 14. The registration system according to claim 1 wherein said electromechanical means includes a servomotor having a rotatable output shaft coupled to the differential drive means, said servomotor having an energizable electromagnetic circuit determinative of the rotary condition of said output shaft, said electromagnetic circuit being energized by the electric signal for determining the rotary condition of the output shaft.
 15. The registration system according to claim 1 wherein said electromechanical means includes a torque amplifier interposed between the output shaft of said servomotor and said differential drive means and containing said output member, said torque amplifier amplifying the rotary condition of said servomotor output shaft.
 16. The registration system according to claim 15 wherein said torque amplifier includes a primary power source independent of said differential drive means.
 17. A registration system for providing registration between successive portions of a moving web and a web-treating apparatus cyclically applied to each of the web portions, said web-treating apparatus having controllable metering rolls located upstream along the web for regulating the length of the web portion provided to the web-treating apparatus during each cycle of operation and the registration of the portions with the apparatus in accordance with the rotary condition of the rolls, said web-treating apparatus further having a registration error detector for detecting the registration error between the web-treating apparatus and the successive portions of the web and providing an error signal accordingly, said web-treating apparatus having a differential drive means for establishing a rotary condition of the metering rolls, said registration system comprising: a signal-converting means having an input responsive to the error signal of the registration error detector for converting the error signal into an output signal corresponding to a registration correcting alteration in the rotary condition of the metering rolls; said registration error detector providing a periodic error signal in accordance with a predetermined cumulative registration error occurring over sequential cycles of operation of the web-treating apparatus and wherein said signal-converting means comprises means for converting the periodic error signal into a continuous output signal responsive to the occurrence of the error signal, said signal-converting means includes a signal-generating means for providing a signal and a signal-altering means cooperable therewith, said signal-altering means containing said signal-converting means input and being operable by the error signal for altering the signal-generating means signal to convert the error signal into said output signal, a tachometer for measuring the speed of the moving web and for providing a speed signal proportional to the speed of the web and wherein said signal-generating means is energized by the speed signal of said tachometer, and electromechanical means coupled to said signal converting means and having a controllable output member responsive to said output signal, said output member being drivingly connected to the differential drive means for altering the rotary condition of the metering rolls to provide registration between the web portions and the web-treating apparatus. 